"Buprenorphine is a long-acting partial opioid agonist91,92 that is classified as a Schedule III narcotic, in contrast to methadone and levomethadyl, which are Schedule II. Its potential advantages include a higher degree of safety than with methadone, coupled with an ameliorated withdrawal syndrome. This is due to its partial agonist property at the ?-receptor along with its being a weak antagonist at the k-receptor.93-95 It is available in a tablet form for sublingual administration and in parenteral form. Buprenorphine is metabolized through the cytochrome P450 pathway.96-97 The brand name for the buprenorphine monotablet is Subutex, and the combination buprenorphine hydrochloride–naloxone hydrochloride tablet is Suboxone (both Reckitt Benckiser Pharmaceuticals, Richmond, Va). Both formulations come in strengths of 2 and 8 mg. The combination product contains 0.5mg of the opioid antagonist naloxone hydrochloride and is designed to decrease the potential for abuse."
Mori J. Krantz, MD; Philip S. Mehler, MD, "Treating Opioid Dependence: Growing Implications for Primary Care," Archives of Internal Medicine, (Chicago, IL: American Medical Association, February 2004), Vol. 164, p. 281.